Remote control system



y 1929- L. E. COON 1,711,672

REMOTE CONTROL SYSTEM Filed July 27, 1925 2 yMmMAf/y Patented May 7,1929.

UNITED STATES PATENT OFFICE.

LESLIE E. .OOON, OF CHATHAM, NEW JERSEY, ASSIGNOR TO WESTERN ELEGTBTGCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

REMOTE CONTROL SYSTEM.

Application filed July 27, 1925. Serial No. 46,274.

This invention relates to remote control systems and its object is toprovide a system whereby the operator at a central station may exercisevery close control of apparatus at a distant station.

In remote control systems now in use, a device such as a power switch ata substation can be operated from the dispatchers station byinaugurating a series of events which involves the operation of a numberof relays, selectors, etc., and to return such a device to its originalcondition a similar series has to be gone through. Such systems areadapted primarily to change the position of a power switch from closedto open position or vice versa and permit no intermediate variations inthe operation. These systems are not well adapted to remote controlsystems in which the control to be exercised is very close as, forexample, in hydro-electric power plants where the flow of water throughturbines requires close adjustment or in some stations where the loadcarried by a generator is to be varied.

The present invention provides a remote control comparable to that whichcould be exercised by an attendant directly operating the device to becontrolled.

In the present embodiment of this invention, each of the generators hasassociated with it a pair of devices to raise or lower the load, andalso a pair of selectors. The selectors are stepped around under controlof a transmitter at the central or dispatchers station until one of theselectors is one step short of selecting the associated device in whichposition it is held when the impulses stop, the other selectorsrestoring in the well known way. A key is then operated by thedispatcher to give the held selector another step in which position itsarm closes a circuit to operate a relay which starts the device, whichmay be a motor, to operate means to change the generator output to thedesired extent whereupon release of the key stops. the motor due to theselector moving back one step.

This invention will be better understood from the following descriptionin connection form of the invention; Fig. 2 represents a portion of thestepping selector in one position while Fig. 3 represents the sameportion of the selector in another position.

Referring to Fig. 1, A represents a central station located at a pointdistant from a remote station B. At the remote station are two devices 1and 2 the action of which is to be controlled from station A.

The drawing represents a system for load control which may beaccomplished by changing the field resistance of generators. The systemis not limited to use in such connection but its application to a powersystem wherein the field resistance of generators is varied has beenillustrated to simplify its description.

Devices 1 and 2 are represented as motors, 1 being referred to as araise load device while 2 is referred to as a lower load device. Thesedevices are arranged to vary the resistance 31 of generator 32 bymeanaof cooperatlng gears 33 and 34, threaded shaft 35. actuatingsliding contacts 36 and 37 in an obvious manner.

At station. A are two transmitter keys 3 t and 4 adapted to controlrespectively devices 1 and 2. The transmitter keys are in a localcircuit arranged to operate relay 5 which is of the pole changer typeadapted to impress on line wires 6 and 7 impulses of alternate polarityfrom a current source 8. At station B these impulses are impressed onselectors such as 9, to operate them to within one step of closing acircuit, the closing of which circuit operates a relay such as 10 tostart device 1 or 2. The apparatus associated with device 1 isdesignated generally by 30 while rectangle 11 represents anotherselector, relay, con'denser etc, associated with device 2. The selectorsillustrated are of the type disclosed in Patent No. 1,343,256 to J. 0.Field, dated June 15, 1920. It is understood that the system is notlimited to such selectors but any selector ofa similar type may be used.

A key 12 at station A gives the final pulse to step the arm 13 ofselector 9 at station E the one step required to contact with thecontact 14c. As explained in the above mentioned patent, if contact ofkey 12 is broken at statlon A, the selector arm will not return to itsnormal position but will drop back but one step so that if the key 12 isagain operated arm 13 again contacts with contact 14 to cause relay 10to operate which again operates motor device 1. x

This action will be more clearly understood by referring to Figs. 2 and3. In Fig. 2 the selector mechanism is shown in the position it assumesat the cessation of the last pulse caused by the transmitter. Armature38 is in the neutral or unoperated position, contact arm 13 carried bywheel 39 is within one step of making contact with contact 14. Wheel 39is held in this position by means of piece 40 attached to wheel 39 whichis engaged by holdinig arm 41. It is to be understood of course thattransmitter 4 sends a different number of impulses than transmitter 3.In other words a given number of impulses which step selector 9 aroundto the point where it will be held by the member 40 will not cause theselector 11 to be held since at that moment'the member 40 ofselector 11is not opposite the holding arm 41 of selector 11. When the next pulseis sent through the selector windings (caused by operating key 12Fig. 1) armature 38 takes up a position such as that shown in Fig. 3.Arm 42 attached to armature 38 is provided with two pins 43 and 44. Inthe position shown in Fig. 3 pin 43 has moved arm 45, thereby causingpawl 46 attached to arm 45 toengage one of the teeth 47 on wheel 39which moves the wheel one step to make contactbes tween arm 13 andcontact point 14. This same action would have been caused if armature 38had beenattracted by the core of the other winding. In this case pin 44would have caused the movement of arm 45. Upon the cessation of thepulse (when contact at key 12 is broken Fig. 1) the armature resumes itsneutral position and the associated mechanism returns to the positionshown in Fig. 2. 1

The operation of the system is as follows: Assume that it is desired toraise the load. Transmitter key 3 marked Raise Fig. 1 is caused torotate. As soon as the transmitter cam moves, contact is made between itand contact arm 15 which closes a circuit from battery 16, conductor 17,contact arm 15, cam

of transmitter 3, conductor 18 winding of relay 19, conductor 20 tobattery 16. Relay 19 is therefore energized and in operating pulls upboth armatures. At its left armature it closes an obvious circuit tooperate relay 21 which removes the chargingisource from battery 8 toprovide against any surges etc., which might be impressed on the linefrom the-chargmg source. At its right armature relay- 19 closes anobvious circuit through relay 22 to-operate it and hence connect battery8 through contacts and armatures of relay 5 to the transmission line.

-As the transmitter key continues to rotate contact is made and brokenbetween arms 15 and 23 to alternately energize and deenergize relay 5over a circuit from battery 16, conductor 17, contact arms 15, 23,conductor 24, winding of relay 5, conductor 20 to battery 16. Relay 5being of the pole changer type, upon energizing and deenergizingimpresses impulses of alternate polarity on selector 9 at station B fromcurrent source, or battery, 8. This circuit may be traced from battery8, front or back contact and left armature of relay 5, left armature andfront contact of relay 22, line wire 6, conductor 25, windings ofselector 9, condenser 26, conductor 27, line wire 7 right armature andeither front or back contact of relay 5 to battery 8. The codetransmitted by key 3 steps selector arm 13 around to within one step ofengagement with contact 14. The transmitter cam then completes itsrotation and returns to its initial position in which position contactarm 15 is out of engagement with thecam and also with arm 23 and hencerelay 19 becomes deenergized. Relays 21 and 22 are also deenergiz'ed,relay 21 again connecting charging source to battery 8 and relay 22disconnecting .the transmission apparatus from the line.

If key 12 at station A is now operated it will have the same effect asthe first step in the operation of transmitter key 3 namely, relay 19will be operated which in turn will operate relays 21 and 22 asdescribed above and for the same reason. However, key 12 has no controlover relay 5 and hence current flows over line Wires 6 and 7 in but onedirection. This pulse controlled by key 12 steps selector arm 13 intoengagement with contact 14 and closes a circuit from battery 28 throughrelay 10 over an obviouscircuit. At

its left armature relay 10 closes a shunt circuit around condenser 26which will have become charged by the continuous flowing current. Ifthis shunt circuit were not provided currentlwould cease to flow whencondenser 26 became charged and selector arm 13 would drop back fromcontact 14.

At its left armature relay 1O closes an obvious circuit from currentsource 29 to cause the operation of raise road device 1.

If key 12 is now caused to break its circuit relay 22 will open thecircuit through. the selector windings and thereby permit selector arm13 to drop back one step breaking the energizing circuit for relay 10which upon deenergization opens the circuit for raise load device 1. Ifrequired, key 12 may again be operated to cause the operation of device1.

With the necessary indicators at station A the load at station B may bere ulated within very close limits by means of key 12. After theload-has been properly regulated the selector arm is returned to itsinitial position by again operating the "transmitter key 3. Since nowthe selector arm is not in its initial position it will not be at astopping point when the transmitter key has ceased transmitting and thearm will therefore return to its initial position.

The code which transmitter key 4 is adapt-- ed to transmit will actuatethe selector controlling the -lower load device 2 represented ascontained in 11. The other operations are identical with those justdescribed in connection with the raise load device.

This system may be modified in various ways to accomplish this purposeand the above description and drawing refer to but one embodiment of theinvention which is limited only by the scope of the following claims.

What is claimed is:

1. In combination, a central station, a remote station, devices to beregulated, electromagnetic means for controlling said devices, selectorsand operating means therefor, a circuit including said selectoroperating means, each selector operating means, having a condenser inseries therewith, means at the central station for impresisng a code ofimpulses of alternate polarity on said circuit to'cause one of saidselectors to select one of said elec tromagnetic means, muiti-contactrelays at said remote station, one for each selector operated thereby toshort-circuit the associated condenser at one of its contacts in theselecting position, a circuit closed at a second contact of said relayand including the associated electromagnetic means, and means includinga key at the central station for controlling said selector to hold saidcircuit closed.

2. A remote control system comprising a central station and a remotestation, line conductors joining said stations, devices at said remotestation motors thereat for regulating same, impulse transmitters at saidcentral station, selectors at said remote station responsive to codes ofimpulses sent out by said impulse transmitters to be actuated within onestep of selecting the corresponding motor, a key at said centralstation, a circuit controlled by said key for giving the impulserequired to move said selector another step and thereby to select saidmotor, and means tending normally to restore the selector, said selectorhaving means to hold it one step from the selecting position when saidcircuit is opened by said key.

3. A remote control system comprising a central station and a remotestation, line conductors joining said stations, a generator at theremote station to be regulated, means including a pair ofmotors at saidremote station for raising and lowering the load on. said generatorrespectively, a relay for each motor for controlling the same,step-by-step selector switches at said remote station each having meansadapted to operate one of said relays when in its operated position,means including transmitter keys at the central station adapted toactuatesaid selector switches to within one step of selecting thecorresponding motor to start the same, means including a key at saidcentral station adapted when operated to step the selector switch onestep to select said motor, and means tending normally to restore theselector switch, said switch having means to hold the selector switchone step from the operated position upon release of the key.

4. In a control system, a line circuit, a controlled device comprisingan actuating coil supplied through said line circuit, a condenser in thecircuit of said coil, a source of direct current, means for holding saiddevice in a predetermined position after it has been moved to saidposition by said actuating coil, means adapted to effect the connectionof said source to said line circuit so that the proper series ofimpulses are produced through said actuating coil to eflect the movementof said device to said predetermined position, means for connecting saidline circuit to said source to effect movement of said device from saidpredeterminedposition to another position, and means for completing ashort-circuit around said condenser when said device is in said lastmentioned position.

5. i In a control system, a line circuit, a controlled device comprisingan actuating coil connected to said line circuit, a. condenser in thecircuit of said coil, a source of direct current, means for holding saiddevice in a predetermined position after it has been moved to saidposition by said actuating coil, means adapted to effect the connectionof said source to said line circuit so that the proper series ofimpulses are produced through said actuating coil to efiect the movementof said device to said predetermined position, means for connecting saidline circuit to said source to effect movement of said device from saidpredetermined position to another position, a control relay, a circuitfor said control relay, contacts in said control relay circuit arrangedto be closed when said device is in said last mentioned position, and acircuit around said condenser arranged to be completed in rezlsponse tothe energization of said control re ay.

In witness whereof, I hereunto subscribe my name this 25th day of July,A. D. 1925.

LESLIE E. COON.

